Generally, a metal plate is used to form exteriors of various household appliances such as a refrigerator, a washing machine, a dish washer, an oven, and so on.
A type of the metal plate capable of forming the exterior of the household appliance may be appropriately selected according to an application. The type of the metal plate may include aluminum or an alloy thereof, copper or an alloy thereof, steel or an alloy thereof, zinc or tin-coated aluminum, copper or steel, a zinc or tin alloy, stainless steel, and so on.
Currently, in competition between companies developing the household appliances, designs and sizes of the household appliances may serve as a major factor in selecting the household appliances.
In particular, a surface of the metal plate capable of forming the exterior of the household appliance may be designed differently by forming various patterns thereon through a surface treatment to have beautiful exteriors.
Generally, the surface treatment of the metal plate may prevent glare caused by a specific gloss of metal generated on the surface of the metal plate and may enhance the quality of the household appliance.
Such a surface treatment method may include a hairline patterning method corresponding to one aspect of a design competition of the household appliances. The hairline patterning method may correspond to a method of forming a hairline pattern which is a line formed continuously and long like a hair on the surface of the metal plate.
The hairline pattern formed to have uniform density and thickness may increase a design value of the household appliance.
Generally, a hairline process forming the hairline pattern may correspond to a method of forming a directional streak on the surface of the metal plate by a mechanical method to leave an abrasive mark continuously on the surface of the metal plate using an abrasive and finishing the surface treatment.